2
\$\begingroup\$

Doesn't look like "Synchronous Ethernet" exist over wireless like it does on wired. Is there any technical reason for it not existing?

On wired, Synchronous Ethernet transfers a 125 MHz master clock to the children for synchronization. Is there any reason why we can't do the same thing in a wireless system?

Edit: Completely reworded question because I didn't get any answers.

\$\endgroup\$
1
\$\begingroup\$

This is an interesting question.

SyncE is derived from standard full-duplex Ethernet - with some alterations to the PHY, that make it incompatible with peers that do not run SyncE. But if two SyncE-compliant peers set up a working L1 link, they can of course transport Ethernet frames.

What is wireless Ethernet? Let's speak 802.11. AFAICT, all standard 802.11 from "b" to "ac" work in a single frequency channel with CSMA-CA, i.e. in a half-duplex fashion. There's no single station that would keep transmitting an isochronous bitstream. You'd have to invent an 802.11 derivative with frequency-divided uplink and downlink, where probably the AP would transmit an isochronous bitstream on its carrier frequency, and all the client stations would latch onto that. If I understand correctly, there's no need for the SyncE slave to transmit an isochronous stream to its uplink peer (master) so there's no need to bother (much) with the uplink direction - although some problems remain to be addressed, stemming from concurrency in the uplink direction, the need for retransmissions in the standard media access scheme of the 802.11 wifi etc. The slaves would need to update the PTP timestamp on each retransmission attempt, or maybe it would fit in with some (custom) TDMA scheme for the uplink etc.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.